The impact of the COVID-19 pandemic on the Ontario Cervical Screening Program, colposcopy and treatment services in Ontario, Canada: a population-based study.

OBJECTIVE: To describe the immediate impact of the COVID-19 pandemic on cervical screening, colposcopy and treatment volumes in Ontario, Canada. DESIGN: Population-based retrospective observational study. SETTING: Ontario, Canada. POPULATION: People with a cervix age of 21-69 years who completed at least one cervical screening cytology test, colposcopy or treatment procedure for cervical dysplasia between January 2019 and August 2020. METHODS: Administrative databases were used to compare cervical screening cytology, colposcopy and treatment procedure volumes before (historical comparator) and during the first 6 months of the COVID-19 pandemic (March-August 2020). MAIN OUTCOME MEASURES: Changes in cervical screening cytology, colposcopy and treatment volumes; individuals with high-grade cytology awaiting colposcopy. RESULTS: During the first 6 months of the COVID-19 pandemic, the monthly average number of cervical screening cytology tests, colposcopies and treatments decreased by 63.8% (range: -92.3 to -41.0%), 39.7% (range: -75.1 to -14.3%) and 31.1% (range: -43.5 to -23.6%), respectively, when compared with the corresponding months in 2019. Between March and August 2020, on average 292 (-51.0%) fewer high-grade cytological abnormalities were detected through screening each month. As of August 2020, 1159 (29.2%) individuals with high-grade screening cytology were awaiting follow-up colposcopy. CONCLUSIONS: The COVID-19 pandemic has had a substantial impact on key cervical screening and follow-up services in Ontario. As the pandemic continues, ongoing monitoring of service utilisation to inform system response and recovery is required. Future efforts to understand the impact of COVID-19-related disruptions on cervical cancer outcomes will be needed. TWEETABLE ABSTRACT: COVID-19 has had a substantial impact on cervical screening and follow-up services in Ontario, Canada.

Melatonin ameliorates spatial memory and motor deficits via preserving the integrity of cortical and hippocampal dendritic spine morphology in mice with neurotrauma.

We aimed to elucidate the role of cortical and hippocampal dendritic spines on neurological deficits associated with hippocampal microgliosis, hippocampal neurogenesis, and neuroinflammation in mice with cortical compact impact (CCI) injury. In the present study, we found that CCI reduced spatial memory mean latency (10 s. vs 50 s) and motor dysfunction (130 s. vs 150 s.) in mice, as determined by Morris water maze and rotarod test, respectively. Golgi staining of cortical pyramidal neurons revealed that, compared to the controls, the CCI group treated with vehicle solution had significantly lower values of dendritic order (or dendritic branch number) (4.0 vs 6.2), total spine length (400 µm vs 620 µm) and spine density (40 spines/µm vs 60 spines/µm), but had significantly higher values of dendritic beading (40 beadings/mm vs 20 beadings/mm). Additionally, Sholl analysis showed that, compared to controls, the CCI + NS group mice had significantly lower values of dendritic intersections (1.0 vs 2.0). Immunofluorescence assay also revealed that, compared to controls, the CCI + NS group mice had significantly higher values of the newly formed hippocampal cells (1250/mm2 vs 1000/mm2) but significantly lower values of dendritic order (2.0 branch # vs 4.2 branch #), total spine length (180 µm vs 320 µm) and intersection (1.0 vs 3.0). The CCI + NS group mice further showed significantly higher numbers of microglia in the dentate gyrus of the hippocampus and higher concentrations of pro-inflammatory cytokines in the cerebrospinal fluids. All the CCI-induced spatial memory (40 s) and motor (150 s) dysfunction, deranged dendritic and spine morphology of cortical pyramidal neurons or hippocampal newly formed cells, hippocampal microgliosis, and central neuroinflammation were all significantly reduced by melatonin administration during post-CCI. Simultaneously, melatonin therapy caused an enhancement in the compensatory hippocampal neurogenesis and neurotrophic growth factors (e.g., doublecortin-1) and compensatory central anti-inflammatory cytokines. Our results indicate that melatonin attenuates the spatial memory and motor deficits via the modification of cortical and hippocampal dendritic spine morphology, hippocampal microgliosis and neurogenesis, and neuroinflammation in mice with traumatic brain injury.

Is food allergen analysis flawed? Health and supply chain risks and a proposed framework to address urgent analytical needs.

Food allergy is an increasing problem for those affected, their families or carers, the food industry and for regulators. The food supply chain is highly vulnerable to fraud involving food allergens, risking fatalities and severe reputational damage to the food industry. Many facets are being pursued to ameliorate the difficulties including better food labelling and the concept of thresholds of elicitation of allergy symptoms as risk management tools. These efforts depend to a high degree on the ability reliably to detect and quantify food allergens; yet all current analytical approaches exhibit severe deficiencies that jeopardise accurate results being produced particularly in terms of the risks of false positive and false negative reporting. If we fail to realise the promise of current risk assessment and risk management of food allergens through lack of the ability to measure food allergens reproducibly and with traceability to an international unit of measurement, the analytical community will have failed a significant societal challenge. Three distinct but interrelated areas of analytical work are urgently needed to address the substantial gaps identified: (a) a coordinated international programme for the production of properly characterised clinically relevant reference materials and calibrants for food allergen analysis; (b) an international programme to widen the scope of proteomics and genomics bioinformatics for the genera containing the major allergens to address problems in ELISA, MS and DNA methods; (c) the initiation of a coordinated international programme leading to reference methods for allergen proteins that provide results traceable to the SI. This article describes in more detail food allergy, the risks of inapplicable or flawed allergen analyses with examples and a proposed framework, including clinically relevant incurred allergen concentrations, to address the currently unmet and urgently required analytical requirements. Support for the above recommendations from food authorities, business organisations and National Measurement Institutes is important; however transparent international coordination is essential. Thus our recommendations are primarily addressed to the European Commission, the Health and Food Safety Directorate, DG Santé. A global multidisciplinary consortium is required to provide a curated suite of data including genomic and proteomic data on key allergenic food sources, made publically available on line.

Ventricular arrhythmia incidence in the rat is reduced by naloxone.

This study characterized the antiarrhythmic effects of the opioid receptor antagonist naloxone in rats subject to electrically induced and ischemic arrhythmias. Naloxone (2, 8 and 32 µmol/kg/min) was examined on heart rate, blood pressure, and the electrocardiogram (EKG) as well as for effectiveness against arrhythmias produced by occlusion of the left anterior descending coronary artery or electrical stimulation of the left ventricle. Naloxone reduced blood pressure at the highest dose tested while heart rate was dose-dependently reduced. Naloxone dose-dependently prolonged the P-R and QRS intervals and increased the RSh amplitude indicative of effects on cardiac sodium (Na) channels. Naloxone prolonged the Q-T interval suggesting a delay in repolarization. Naloxone effects were comparable to the comparator quinidine. Naloxone (32 µmol/kg/min) reduced ventricular fibrillation (VF) incidence to 38% (from 100% in controls). This same dose significantly increased the threshold for induction of ventricular fibrillation (VFt), prolonged the effective refractory period (ERP) and reduced the maximal following frequency (MFF). The patterns of ECG changes, reduction in ischemic arrhythmia (VF) incidence and changes in electrically induced arrhythmia parameters at high doses of naloxone suggest that it directly blocks cardiac Na and potassium (K) ion channels.

Combination of Dasatinib and Quercetin alleviates heat stress-induced cognitive deficits in aged and young adult male mice.

OBJECTIVE: Dasatinib and quercetin (D & Q) have demonstrated promise in improving aged-related pathophysiological dysfunctions in humans and mice. Herein we aimed to ascertain whether the heat stress (HS)-induced cognitive deficits in aged or even young adult male mice can be reduced by D & Q therapy. METHODS: Before the onset of HS, animals were pre-treated with D & Q or placebo for 3 consecutive days every 2 weeks over a 10-week period. Cognitive function, intestinal barrier permeability, and blood-brain barrier permeability were assessed. RESULTS: Compared to the non-HS young adult male mice, the HS young adult male mice or the aged male mice had significantly lesser extents of the exacerbated stress reactions, intestinal barrier disruption, endotoxemia, systemic inflammation and oxidative stress, blood-brain barrier disruption, hippocampal inflammation and oxidative stress, and cognitive deficits evaluated at 7 days post-HS. All the cognitive deficits and other syndromes that occurred in young adult HS mice or in aged HS mice were significantly attenuated by D & Q therapy (P < 0.01). Compared to the young adult HS mice, the aged HS mice had significantly (P < 0.01) higher severity of cognitive deficits and other related syndromes. CONCLUSIONS: First, our data show that aged male mice are more vulnerable to HS-induced cognitive deficits than those of the young adult male mice. Second, we demonstrate that a combination of D and Q therapy attenuates cognitive deficits in heat stressed aged or young adult male mice via broad normalization of the brain-gut-endotoxin axis function.

The forensic implications of food hypersensitivity - a review of cases in United Kingdom courts: January 2014-February 2020.

AIMS: Food allergy is a major public health concern. Failures of food allergen avoidance and the consequences for those with food hypersensitivity (allergies, intolerances and coeliac disease) have a forensic context. The aim of this study was to collate and analyse the use of action in the United Kingdom (UK) courts as redress following adverse food allergy reactions or failures of allergen management. METHODS: Details of prosecutions during the study period (1 January 2014 to 31 January 2020) were recorded from regular key word Internet searches. National and local news reports were primary sources, along with commentary from enforcement and regulatory professionals. Information was also collected from coroners' inquests by attending hearings and direct contact with coroners and participants in the hearings. Freedom of Information requests were made to local authority enforcement departments. In several cases, the authors had direct involvement in investigations. RESULTS: From 2014 to 2020, there was an increase in reports. Seventy prosecutions were recorded as well as two associated appeals and two applications for Hygiene Emergency Prohibition Notice. This resulted in 68 convictions; seven individuals received custodial sentences, three of which were suspended although one individual had a tagged curfew imposed. Fines ranged from £50 to £93,000. Details of the law applied and the evidence gathering processes are reported. CONCLUSION: Legal action, including landmark prosecutions for Gross Negligence Manslaughter and Preventing Future Deaths reports from coroners, with salience of criminal penalties, has led to changes in labelling law and improved allergen management practices better to protect the interests of patients with food hypersensitivities. A central system of collation of such data, and on 'near misses', will enable more focused root cause analysis to further improve allergen management and reduce patient risk.

Honey authenticity: the opacity of analytical reports-part 2, forensic evaluative reporting as a potential solution.

The analytical techniques applied to verify honey authenticity are multifaceted and often result in complex data rich certificates of analysis that are open to interpretation and may be opaque to stakeholders without specialist knowledge. In these cases, the drawing of an independent overarching opinion is challenging. Two questions arise: (Q1) Is it acceptable to report interpretation, particularly if it is adverse, without exhibiting the supporting data? (Q2) How may a valid overarching opinion on authenticity be derived from a large, partially conflicting, dataset? To Q1, it is demonstrated that full disclosure of the data used in interpretation is mandatory. To Q2 it is proposed, with worked examples, to adopt 'evaluative reporting'; a formalised likelihood ratio thought process used in forensic science for evaluation of findings and their strength assessment. In the absence of consensus on techniques for honey authenticity adoption of reporting conventions will allow objective assessments of reports, with equity to all and provide a better basis to identify and address fraud.

Honey authenticity: the opacity of analytical reports - part 1 defining the problem.

The composition of honey, a complex natural product, challenges analytical methods attempting to determine its authenticity particularly in the face of sophisticated adulteration. Of the advanced analytical techniques available, only isotope ratio mass spectrometry (IRMS) is generally accepted for its reproducibility and ability to detect certain added sugars, with nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) being subject to stakeholder differences of opinion. Herein, recent reviews of honey adulteration and the techniques to detect it are summarised in the light of which analytical reports are examined that underpinned a media article in late 2020 alleging foreign sugars in UK retailers' own brand honeys. The requirement for multiple analytical techniques leads to complex reports from which it is difficult to draw an overarching and unequivocal authenticity opinion. Thus arose two questions. (1) Is it acceptable to report an adverse interpretation without exhibiting all the supporting data? (2) How may a valid overarching authenticity opinion be derived from a large partially conflicting dataset?

7,8-Dihydroxyflavone accelerates recovery of Brown-Sequard syndrome in adult female rats with spinal cord lateral hemisection.

BACKGROUND: 7,8-Dihydroxyflavone (DHF) mimicks the physiological action of brain-derived neurotrophic factor (BDNF). Since local BDNF delivery to the injured spinal cord enhanced diaphragmatic respiratory function, we aimed to ascertain whether DHF might have similar beneficial effects after Brown-Sequard Syndrome in a rat model of spinal cord lateral hemisection (HX) at the 9th thoracic (T9) vertebral level. METHODS: Three sets of adult female rats were included: sham+vehicle group, T9HX+vehicle group and T9HX+DHF group. On the day of surgery, HX+DHF group received DHF (5 mg/kg) while HX+vehicle group received vehicle. Neurobehavioral function, morphology of motor neurons innervating the tibialis anterior muscle and the transmission in descending motor pathways were evaluated. RESULTS: Adult female rats received T9 HX had paralysis and loss of proprioception on the same side as the injury and loss of pain and temperature on the opposite side. We found that, in this model of Brown-Sequard syndrome, reduced cord dendritic arbor complexity, reduced cord motoneuron numbers, enlarged cord lesion volumes, reduced motor evoked potentials, and cord astrogliosis and microgliosis were noted after T9HX. All of the above-mentioned disorders showed recovery by Day 28 after surgery. Therapy with DHF significantly accelerated the electrophysiological, histological and functional recovery in these T9HX animals. CONCLUSIONS: Our data provide a biological basis for DHF as a neurotherapeutic agent to improve recovery after a Brown-Sequard syndrome. Such an effect may be mediated by synaptic plasticity and glia-mediated inflammation in the spared lumbar motoneuron pools to a T9HX.

miR-21 and miR-155 are associated with mitotic activity and lesion depth of borderline melanocytic lesions.

BACKGROUND: Expression of microRNAs (miRs) has been shown to be altered in many solid tumours and is being explored in melanoma. The malignant potential of some melanocytic lesions is difficult to predict. We hypothesised that characterisation of miR expression in borderline melanocytic proliferations would lead to the identification of a molecular profile that could be used with known prognostic factors to differentiate lesions with high malignant potential. METHODS: The miR expression profile of melanocytic lesions (benign naevi, malignant melanoma and borderline melanocytic tumours) was evaluated by real-time PCR. RESULTS: PCR analysis revealed primary cutaneous melanomas had an 8.6-fold overexpression of miR-21 and a 7.5-fold overexpression of miR-155 compared with benign naevi (P<0.0001). In situ hybridisation confirmed these results. miR-21 and miR-155 were significantly overexpressed within borderline lesions (P=0.0011 and P=0.0048, respectively). When borderline lesions were categorised by mitotic activity and Breslow thickness, miR-21 was associated with mitotic activity and miR-155 was associated with thickness (P<0.025). Among 14 patients with borderline lesions who underwent sentinel lymph node biopsy (SLNB), positive SLNB was associated with increased miR-21 and miR-155 in the primary lesion compared with lesions with a negative SLNB. CONCLUSION: MicroRNA expression profiles can be used to characterise atypical melanocytic lesions.

Myricetin against myocardial injury in rat heat stroke model.

BACKGROUND: Heat stroke-induced mortality is rising across the globe. So, the design of prophylactic and/or therapeutic modalities for heat stroke is pressing need. The common plant derived flavonoid exhibits strong anti-oxidant and anti-inflammatory activities; however, its effects in heat stroke remain unknown. The study aimed to investigate the cardioprotective effects of myricetin on heat stroke induced acute myocardial injury as well as lethality in rats and to explore the underlying mechanisms. METHODS: Myocardial injury was induced by subjecting the anesthetized rats to a high ambient temperature of 43 °C for 70 min. An intragastrical dose of myricetin (5-25 mg/kg body weight) was given to rats once per day for one week prior to the start of heat stress. Heat shock protein 72 antibodies was given intraperitoneally to rats 24 h before the start of heat stress. Myocardial injury severity was estimated by determing myocardial damage scores, myocardial injury indicators, myocardial oxidative and inflammatory factors. Western blot analysis was used for cardiac expression of heat shock protein (HSP)72. RESULTS: Significant (P < 0.05) up-regulation of HSP-72 after chronic administration of myricetin coincided with significant (P < 0.05) reduction in hyperthermia, hypotension, cardiac inflammatory and oxidative damage and lethality. Inhibition of HSP-72 showed a significant (P < 0.05) reversal in the cardiaprotection as well as survival. CONCLUSIONS: Our results indicate that myricetin diminishes myocardial injury as well as lethality in heat stroke by up-regulating HSP-72 and show promise as a novel prevention therapeutic for heat stroke.

Updated emm-typing protocol for Streptococcus pyogenes.

OBJECTIVES: PCR-based typing of the emm gene Streptococcus pyogenes often results in the amplification of multiple bands. This has resulted in the misclassification of strains into types based on non-emm gene sequences. We aimed to improve the specificity of the emm typing PCR reaction using a primer called CDC3, the sequence for which has been previously used to identify emm genes in silico. METHODS: The proposed primer CDC3 was validated in silico from a global database of 1688 GAS genomes and in vitro with 32 isolates. PCR reactions were performed on genomic DNA from each isolate, using the published CDC1 forward primer with the CDC2 reverse primer or the new CDC3 reverse primer. The products were examined by gel electrophoresis, and representative PCR products were sequenced. RESULTS: In 1688 S. pyogenes genomes, the previous CDC2 reverse primer annealed in silico in 1671 emm genes and also in 2109 non emm genes in close proximity, whereas the new CDC3 primer annealed in 1669 emm genes only. The remaining 19 genes without a CDC3 binding site were chimeric emm genes. The PCR pair CDC1+CDC3 produced a single band at appropriate molecular weight in all 32 isolates tested, while the CDC1+CDC2 pair produced more than one band in 13 of 32 isolates (40%). CONCLUSIONS: The new CDC3 primer is more specific for emm genes than the previous CDC2 primer and represents a simple solution to reduce the potential for mistyping S. pyogenes strains.

M protein-mediated plasminogen binding is essential for the virulence of an invasive Streptococcus pyogenes isolate.

The human protease plasmin plays a crucial role in the capacity of the group A streptococcus (GAS; Streptococcus pyogenes) to initiate invasive disease. The GAS strain NS88.2 was isolated from a case of bacteremia from the Northern Territory of Australia, a region with high rates of GAS invasive disease. Mutagenesis of the NS88.2 plasminogen binding M protein Prp was undertaken to examine the contribution of plasminogen binding and cell surface plasmin acquisition to virulence. The isogenic mutant NS88.2prp was engineered whereby four amino acid residues critical for plasminogen binding were converted to alanine codons in the GAS genome sequence. The mutated residues were reverse complemented to the wild-type sequence to construct GAS strain NS88.2prpRC. In comparison to NS88.2 and NS88.2prpRC, the NS88.2prp mutant exhibited significantly reduced ability to bind human plasminogen and accumulate cell surface plasmin activity during growth in human plasma. Utilizing a humanized plasminogen mouse model of invasive infection, we demonstrate that the capacity to bind plasminogen and accumulate surface plasmin activity plays an essential role in GAS virulence.

The antiarrhythmic actions of bisaramil and penticainide result from mixed cardiac ion channel blockade.

Decades of focus on selective ion channel blockade has been dismissed as an effective approach to antiarrhythmic drug development. In that context many older antiarrhythmic drugs lacking ion channel selectivity may serve as tools to explore mixed ion channel blockade producing antiarrhythmic activity. This study investigated the non-clinical electrophysiological and antiarrhythmic actions of bisaramil and penticainide using in vitro and in vivo methods. In isolated cardiac myocytes both drugs directly block sodium currents with IC50 values of 13µM (bisaramil) and 60µM (penticainide). Both drugs reduced heart rate but prolonged the P-R, QRS and Q-T intervals of the ECG (due to sodium and potassium channel blockade) in intact rats. They reduced cardiac conduction velocity in isolated rat hearts, increased the threshold currents for capture and fibrillation (indices of sodium channel blockade) and reduced the maximum following frequency as well as prolonged the effective refractory period (indices of potassium channel blockade) of electrically stimulated rat hearts. Both drugs reduced ventricular arrhythmias and eliminated mortality due to VF in ischemic rat hearts. The index of cardiac electrophysiological balance (iCEB) did not change significantly over the dose range evaluated; however, different drug effects resulted when changes in BP and HR were considered. While bisaramil is a more potent sodium channel blocker compared to penticainide, both produce a spectrum of activity against ventricular arrhythmias due to mixed cardiac ion channel blockade. Antiarrhythmic drugs exhibiting mixed ion channel blockade may serve as tools for development of safer mixed ion channel blocking antiarrhythmic drugs.

Water potential changes in faecal matter and Escherichia coli survival.

AIMS: This study investigated the influence of a range of evaporation rates (2.0, 5.3 and 7.4 mm day(-1)) on degradation of E. coli (ATCC Strain 25922) inoculated in canine faeces. METHODS AND RESULTS: Experiments were carried out in an environmental chamber and a first order exponential decay function (Chick's Law) was used to estimate degradation rates. We estimated die-off coefficients using linear regression. Die-off rates were -0.07, -0.22 and -0.23 h(-1), respectively, for evaporation rates of 2.0, 5.3 and 7.4 mm day(-1) (P = 0.000+, for each model). Nearly complete die-off was found within 15-60 h (7.4-2.0 mm day(-1) evaporation rates), which corresponds with a water potential of approximately -22.4 MPa. CONCLUSIONS: This study indicates that canine faeces need not be desiccated to achieve complete loss of indicator organisms. Water potential, which is a combination of osmotic and matric potential, is a key stress that increases as evaporation removes water from the faecal matrix and increases concentration of the remaining faecal solution. Evaporation may remove populations of indicator organisms in faeces relatively quickly, even though faeces are not completely dehydrated. SIGNIFICANCE AND IMPACT OF THE STUDY: This research may be used as the foundation for studies more closely resembling real-world evaporation conditions including diurnal fluctuations, rewetting and freezing.

Pharmacological and toxicological activity of RSD921, a novel sodium channel blocker.

BACKGROUND: RSD921, the R,R enantiomer of the kappa (k) agonist PD117,302, lacks significant activity on opioid receptors. METHODS: The pharmacological and toxicological actions were studied with reference to cardiovascular, cardiac, antiarrhythmic, toxic and local anaesthetic activity. RESULTS: In rats, dogs and baboons, RSD921 dose-dependently reduced blood pressure and heart rate. In a manner consistent with sodium channel blockade it prolonged the PR and QRS intervals of the ECG. Furthermore, in rats and NHP, RSD921 increased the threshold currents for induction of extra-systoles and ventricular fibrillation (VFt), and prolonged effective refractory period (ERP). In rats, RSD921 was protective against arrhythmias induced by electrical stimulation and coronary artery occlusion. Application of RSD921 to voltage-clamped rat cardiac myocytes blocked sodium currents. RSD921 also blocked transient (ito) and sustained (IKsus) outward potassium currents, albeit with reduced potency relative to sodium current blockade. Sodium channel blockade due to RSD921 in myocytes and isolated hearts was enhanced under ischaemic conditions (low pH and high extracellular potassium concentration). When tested on the cardiac, neuronal and skeletal muscle forms of sodium channels expressed in Xenopus laevis oocytes, RSD921 produced equipotent tonic block of sodium currents, enhanced channel block at reduced pH (6.4) and marked use-dependent block of the cardiac isoform. RSD921 had limited but quantifiable effects in subacute toxicology studies in rats and dogs. Pharmacokinetic analyses were performed in baboons. Plasma concentrations producing cardiac actions in vivo after intravenous administration of RSD921 were similar to the concentrations effective in the in vitro assays utilized. CONCLUSIONS: RSD921 primarily blocks sodium currents, and possesses antiarrhythmic and local anaesthetic activity.

Thyroid hormone insufficiency during brain development reduces parvalbumin immunoreactivity and inhibitory function in the hippocampus.

Thyroid hormones are necessary for brain development. gamma-Amino-butyric acid (GABA)ergic interneurons comprise the bulk of local inhibitory circuitry in brain, many of which contain the calcium binding protein, parvalbumin (PV). A previous report indicated that severe postnatal hypothyroidism reduces PV immunoreactivity (IR) in rat neocortex. We examined PV-IR and GABA-mediated synaptic inhibition in the hippocampus of rats deprived of thyroid hormone from gestational d 6 until weaning on postnatal d 30. Pregnant dams were exposed to propylthiouracil (0, 3, 10 ppm) via the drinking water, which decreased maternal serum T(4) by approximately 50-75% and increased TSH. At weaning, T(4) was reduced by approximately 70% in offspring in the low-dose group and fell below detectable levels in high-dose animals. PV-IR was diminished in the hippocampus and neocortex of offspring killed on postnatal d 21, an effect that could be reversed by postnatal administration of T(4). Dose-dependent decreases in the density of PV-IR neurons were observed in neocortex and hippocampus, with the dentate gyrus showing the most severe reductions (50-75% below control counts). Altered staining persisted to adulthood despite the return of thyroid hormones to control levels. Developmental cross-fostering and adult-onset deprivation studies revealed that early postnatal hormone insufficiency was required for an alteration in PV-IR. Synaptic inhibition of the perforant path-dentate gyrus synapse evaluated in adult offspring, in vivo, revealed dose-dependent reductions in paired pulse depression indicative of a suppression of GABA-mediated inhibition. These data demonstrate that moderate degrees of thyroid hormone insufficiency during the early postnatal period permanently alters interneuron expression of PV and compromises inhibitory function in the hippocampus.

Antiarrhythmic drug research.

This article was written as part of the 75th anniversary celebration of the British Pharmacological Society (BPS). It discusses antiarrhythmic drug research conducted by members of BPS, and as published in the British Journal of Pharmacology (BJP). BPS members, past and present, as well as antiarrhythmic manuscripts published in the BJP have been identified. From these data, the article attempts to semiquantitatively summarize results published in the journal, but only quotes selected manuscripts and individuals. Apologies are offered for omissions and errors, but as in any history, a writer's biases and opinions are unavoidable.

Effects of glucocorticoids on the growth of human fibrosarcoma cell line HT-1080.

The human fibrosarcoma cell line HT-1080 exhibits rapid growth following s.c. inoculation in 4-6-week-old male athymic mice. Cytosols from tumors carried in athymic mice bind glucocorticoid (Kd, 1.8 +/- 0.48 X 10(-8) M; Bmax, 240.5 +/- 35.3 fmol/mg cytosol protein, mean +/- SEM). Receptor sediments primarily in the 8-9S region on 5-20% sucrose gradients and is specific for the glucocorticoids. HT-1080 growth in vitro (as measured by cell count) was inhibited over a range of 10(-6)-10(-8) M after 7 days of incubation with dexamethasone and triamcinolone acetonide. Progesterone, estradiol, and dihydrotestosterone had no effect on HT-1080 growth in vitro. Preincubation with a 100-fold excess of progesterone reversed the growth inhibition observed with triamcinolone acetonide but not dexamethasone acetate. HT-1080 tumor cell growth responded biphasically to dexamethasone in vivo. Athymic mice given s.c. injections every other day with 5 or 25 micrograms dexamethasone showed an increase in tumor size inversely proportional to dose. In contrast, 200 micrograms of dexamethasone significantly inhibited tumor growth. Adrenalectomy did not significantly alter HT-1080 growth or glucocorticoid binding to tumor cytosols (Kd, 3.4 X 10(-8) +/- 1.1, Bmax, 236.9 +/- 9.9 fmol/mg cytosol protein, mean +/- SEM) although tumor incidence was decreased in sham adrenalectomized mice. Glucocorticoid binding in tumors grown in vivo was decreased by increasing amounts of dexamethasone. High pharmacological doses of glucocorticoids inhibit the growth of human fibrosarcomas in vivo and in vitro.

Effect of 17 beta-estradiol on the growth of estrogen receptor-positive human melanoma in vitro and in athymic mice.

Physiochemical properties of an estrogen binding protein were characterized in three human melanoma cell lines, UISO-MEL-1, UISO-MEL-2, and UISO-MEL-4. Estrogen binding to melanoma cytosol was saturable, specific for estrogens, and represented by a single class of high-affinity, limited-capacity binding sites (Kd 5.5 x 10(-10) M, 2.7 +/- 0.5 fmol/mg of cytosol protein, UISO-MEL-2; 2.2 x 10(-10) M, 7.8 +/- 3.3, UISO-MEL-4) (SEM). UISO-MEL-1 cytosols did not bind estradiol. The binding protein in UISO-MEL-2 and -4 sedimented at 8.5S and 9.2S, respectively, in the presence of 10 mM sodium molybdate. Solid-phase radioimmunoassay with a monoclonal antibody specific for human estrogen receptor (H222 sp lambda) showed good correlation (r = 0.84) with a hydroxyapatite biochemical assay of identical melanoma cytosols. Exposure of UISO-MEL-2 to estradiol produced a time- and temperature-dependent increase in total nuclear receptor for estrogen in vitro. Estradiol treatment of athymic mice also significantly increased cytosol progesterone receptor content in UISO-MEL-2 and UISO-MEL-4 xenografts. Estradiol had no effect on the plating efficiency or growth of any melanoma cell line or normal melanocytes in vitro. Tamoxifen also had no effect on melanoma growth in vitro. In contrast, chronic exposure of athymic mice carrying estrogen receptor-positive UISO-MEL-2 to estradiol resulted in a sex-dependent increase in tumor latency and overall inhibition of tumor growth. Taken together, these observations suggest that a subset of human melanomas contains limited amounts of an estrogen binding protein similar to that observed in other estrogen-responsive tissues. The lack of effect of estradiol on melanocyte and melanoma growth in vitro, coupled with a decrease in tumor growth in athymic mice, suggests that, while inhibition may be receptor mediated, possible indirect actions of estradiol must also be considered.